FCC Approves Digital Radio, Kills Satellite Merger

n8willis writes "...Just saw this AP article on Excite news: the FCC has just approved the first upgrade in broadcast radio technology in decades. It allows "CD quality" digital signals to be simulcast by stations along with their traditional analog feed. The tech comes from some company called iBiquity, and unlike Sirius or XM satellite radio, there will be no charge for listening. Some radio buff want to tell us what they know about this concept?" And wiredog writes "The Federal Communications Commission has voted 4-0 to reject a $26 billion merger between satellite TV providers Echostar Communications and Hughes Electronics.

Comments

Re:Sigh

[orev]

These 2 things aren't even related.

Satellite lets you have all the channels no matter where you are in the coutry, and you have to pay for it.

The new digital FM is just an upgrade to regular FM, so you'll get some better sound and maybe a digital readout of what's playing. You still get to listen to the same crappy programming.

There's no "will they ever learn" here. It's 2 completely different things.

IBOC

[David E. Myers]

This technique is also called IBOC, for In-Band On-Channel, since it coexists with existing analog signals. The brand name for the service is HD Radio.

Can it be "CD-quality" at about 96 kbps? We'll see.

A good site for learning more about IBOC is Radio World Online.

Re:4 voting members?

[TheMatt]

Well, you are right. According to the FCC:

The FCC is directed by five Commissioners appointed by the President and confirmed by the Senate for 5-year terms, except when filling an unexpired term. The President designates one of the Commissioners to serve as Chairperson. Only three Commissioners may be members of the same political party. None of them can have a financial interest in any Commission-related business.

But, the FCC also acknowledges that there are only four commissioners at this time. I guess the Senate must be debating the fifth? Anyone know why there's four at the moment?

Re:4 voting members?

[IEEEmember]

FCC site shows only 4 commisioners are currently appointed. FCC is typically run by 5 commisioners.

Michael K. Powell
Kathleen Q. Abernathy
Michael J. Copps
Kevin J. Martin
Additional Information

Read their site.

[Andy Dodd]

http://www.ibiquity.com/navframe.html?03content.ht ml

I have to be careful not to say too much, since as their site is semi-Slashdotted, it's hard to say how much of this is public info and how much is "iBiquity proprietary" (I work at one of iBiquity's equipment partners, and have been working closely with some aspects of their system)

Basically, when the FCC allocated the current FM spectrum, they allowed for a LOT of channel spacing for special features in the analog sidebands and also to take into account inferior receivers/bad transmitters.

Modern transmitters can now output a much cleaner spectrum. Specifically, the FCC allocated a "guard band" around each FM channel, where an ideal FM station shouldn't have emissions but is allowed to "spill over". The guard band power can only be 1/100 of the power of the main band, but thanks to the SNR advantages of digital modulation, a digital signal needs only around 1/100 the power of an FM signal for the same range.

So IBOC can allow an FM signal and a digital signal to coexist on the *same* channel. A cleaned-up FM signal in the main band, and a digital signal in the "guard bands".

An eventual upgrade path is an all-digital signal, replacing the FM portion with a digital signal for greater bandwidth. This is a while off, due to the compatibility issues and also due to technical issues.

Re:Read their site.

[Andy Dodd]

That's probably your receiver. It most likely has an extra-wide IF passband/bad frontent filtering that is simply allowing the main carrier to pass.

In addition to the "guard band", the FM band has insanely wide channel spacing. Transmissions in the guard band that meet spec won't be noticed by your receiver, but if the main carrier itself is strong enough, it'll punch through your frontend filtering, no matter how clean its spectral purity is you'll be screwed. "Adjacent channel power", i.e. emissions on the next proper channel over, is basically not allowed for FM stations.

Re:Map of the radio spectrum?

[wheatking]

Office of Spectrum Management (i kid you not) @

http://www.ntia.doc.gov/osmhome/osmhome.html

Chart @

http://www.ntia.doc.gov/osmhome/allochrt.html

Useful links @

http://www.ntia.doc.gov/osmhome/sites.html

-wk

More info at Wired

[dirvish]

2 good articles over at Wired. One on the approval of the digital standard and another on the merger rejection.

Re:why can't they make more FM quality stations?

[EmagGeek]

Each FM station is currently allocated 200kHz of spectrum in the united states. The FM band currently sits between 88 and 108MHz, inclusive. That leaves 99 channels 200kHz wide a piece.

That's a lot of channels

Now, the reason that you can't have 99 radio stations in a given market is because the FCC has established what are called Basic Trade Areas, or BTAs. Each station on a given frequency is assigned a BTA that is determined by running a longley-rice propagation model based on tower height and the effective isotropic radiated power, EIRP. There are 3 classes of FM stations, and each is allowed a certain tower height and a certain EIRP. Once the propagation model is run, it is overlaid with the US Census Bureau's population density models to determine how many people that FM station will cover. Once that FM station is given its BTA with so many recipients, any new station that applies for a construction permit, REGARDLESS OF THE FREQUENCY OR LOCATION, must PROVE that it will not interfere with that stations BTA, if the propagation model run on that proposed station shows at all that it will be throwing power into the established station's BTA in a manner that will reduce the number of people who can receive the established station. Due to the nasty nature of reactance modulated radio (FM), there is a high potential for intermodulation distortion, third order products, and many other nasty phenomena that will cause interference to desired stations. The capture effect of FM can mitigate this to some degree, and this effect is precisely the reason FM was chosen for its band.

Herein lies a problem with massive digital broadcasting. Sure, if you chose a datarate, say 128kbps, and used digital modulation such a QPSK, 16QAM, or some other amplitude/phase modulated signal, you would use less spectrum, but you have to be MUCH more careful about interference and signal to noise ratio. FM does not require a huge S/N ratio to work, and it only has to be about 3dB above an on-frequency interferer for the capture effect to fix the problem. However, digital modulation methods aren't so immune. In the case of something like 256QAM, the symbols are very close to each other in magnatude and phase, so it doesn't take much noise to corrupt a symbol.

It should also be noted that the FCC has settled on an amplitude modulated method (8VSB) for DTV in the US while Europe uses COFDM, which is a lot more like FM (because it's orthogonal, COFDM has much less intersymbol interference). I'm aware of tests run by a consulting firm in the DC area that showed conclusively that COFDM was the better choice over 8VSB. FM is also used for the audio subcarrier in analog television.

So, the moral of the story is, you can't just have more.... :)

5th commissioner being held up by politics

[dcgaber]

This is a very timely question. It is answered in this article and this op-ed.

Basically, because Senator Leahy is holding up several judicial nominees, the Republican have fired back and put holds on several Democrat nominees, including Jonathan Adelstein, a staffer for Senate Majority leader Daschle and the current nominee for the 5th FCC spot.

Traditionally, the FCC is filled with 5 commissioners, the majority and minority leader of the House and Senate choosing one each, and the President choosing the Chair.

This is actually a big mess right now and causing some to observe they have not seen this type of rancor EVER in the Senate (and that is saying a lot).

Meanwhile a gripe about the moderation system. I think it is ridiculous I can't mod any posts under this article now that I have chosen to add something to it. I comment on articles I am interested in, and I mod in threads I am interested, but I can't do both...that sucks (and yes, I understand the reasons to do so. But given the choice, I would rather comment than mod, but the best is to be able to do both).